This invention relates to radiating elements and antennas and, more particularly, to forms of dual-dipole single-feed radiating elements having a U configuration.
For a variety of reasons it is desirable to provide highly reliable, low cost antennas suitable for meeting the requirements of cellular communication applications. As a result of operational characteristics of cellular systems, spurious intermodulation effects which may be produced in antennas at electrical contact points are particularly undesirable. Contact points or physical connections existing where radiating elements are interconnected or are connected to feed lines may give rise to such intermodulation products. Intermodulation product (IMP) problems may thus result from bimetallic contacts, corrosion effects over time, and combinations of materials resulting in contact points with semiconductor-like characteristics.
While simplicity of construction and low cost construction are common objectives in antenna design, in cellular applications such objectives may directly correspond to considerations important to achieving the lowest levels of intermodulation effects. Thus, a complex, many component antenna may provide a variety of possible sources of intermodulation effects. Conversely, if a simple one-piece radiating element construction could be provided with a reduced number of component contact points, sources of intermodulation effects would be avoided. At the same time, benefits of low cost and ease of assembly could also be achieved. Many of these objectives are achieved in copending application Ser. No. 08/518,059, titled "Low Intermodulation Electromagnetic Feed Cellular Antennas" and commonly assigned with the present application.
Objects of the present invention are to provide new and improved radiating elements and antennas utilizing such elements having one or more of the following advantages or characteristics:
dual-dipole U configuration; PA1 one piece element and feed construction; PA1 short length single conductor feed; PA1 self-supported by short feed conductor; PA1 low profile from back reflector; PA1 unitary element stamped from sheet stock; and PA1 an array of radiating elements, with interconnecting signal distribution network, producible in one piece from brass or other conductive sheet stock. PA1 a first linear conductor segment spaced from and nominally parallel to the reflector; PA1 a second linear conductor segment spaced from and nominally parallel to and coextensive with the first segment, the second segment having one end connected to a first end of the first segment to form a U configuration; and PA1 a feed segment connected at a point along the first segment spaced from the first end thereof, with the feed segment connected to the signal distribution conductor to provide the sole signal feed path to the first and second segments.